Many people suffer from kidney insufficiency or from chronic or acute kidney failure. Although, kidney transplantation is possible in principle, the availability of suitable donor organs is limited and a transplant cannot be carried out for all patients. Thus, methods for washing the blood, known as dialysis, have been developed in the past. The dialysis procedure is characterized in that exchange of substances is carried out by means of a membrane. In this, the fluid to be purified is on one side of the membrane and a suitable dialysate is on the other side.
Various methods have been established in the past. They include hemodialysis, in which urea, ureic acid and other substances are dialysed out of blood using a semipermeable membrane and under the influence of osmotic pressure. Other methods are hemoperfusion, hemodiafiltration and hemofiltration.
Furthermore, the peritoneal dialysis method was also developed in the past. Peritoneal dialysis is also known as PD. The term “peritoneal dialysis” also encompasses various methods such as, for example, manual CAPD (continuous ambulatory peritoneal dialysis), APD (automated PD) or CCPD (continuous cycling PD), which is carried out continuously by machine, IPD (intermittent PD), NIPD (nighttime intermittent PD), etc.
These methods are based on the fact that the peritoneum is a membrane which lines the abdominal cavity and has a good blood supply.
Because of its particular construction, the peritoneum can in fact be used as a “filter membrane.” In this regard, a tube (catheter) is usually implanted in a patient's abdominal cavity. A dialysate is passed via this catheter into the abdominal cavity and left there for a certain period of time. Substances with small molecules can then pass out of the blood via the capillaries of the peritoneum into the dialysate because of the existing concentration gradient After a certain time, the dialysate has to be drained out and replaced with fresh solution.
In contrast to artificial membranes in blood dialysis, the peritoneum is also highly permeable to proteins, whereupon a significant loss of protein occurs.
However, peritoneal dialysis has been shown to be advantageous in many respects. In contrast to other dialysis procedures, peritoneal dialysis allows for lengthier maintenance of any remaining kidney function. In addition, complications are reported less frequently for peritoneal dialysis, because the circulation is stressed to a lesser extent. This is of major advantage for patients with heart problems. In principle, peritoneal dialysis can also be used by patients in their domestic environment, while hemodialysis is only available in specially equipped centres/practices/clinics.
Despite these advantages, peritoneal dialysis is not widespread. Among other things, this can be put down to the fact that reliable, trouble-free operation of the associated machines cannot be guaranteed. Among other things, this can be put down to the fact that the peritoneal dialysis machines suffer from wear and tear which depends on its use, inter alia.